Structure of Tongue: Anatomy and Functions

Structure of tongue is simple in terms of anatomy but it involves different types of muscles. The tongue is organ located in the oral cavity. It not only aids in the perception of gustatory stimuli but also plays key functions in mastication and deglutition. The tongue performs many functions and therefore, it is structured the way that it can perform all activities accurately. Furthermore, the tongue is an essential component of the speech route since it helps in articulation. It is important to note that tongue do not possess any bone in it.

Keyterms: Tongue, organ, mouth, nerves, cells, taste buds, apex, muscles, extrinsic muscles, sulcus

Read More: Difference between Locomotion and Movement

---

Tongue - the organ of the mouth

[Click Here for Sample Questions]

The tongue is a muscular organ that is located in the mouth. It is covered by the mucosa which is a wet, pink tissue . The rough texture of the tongue is caused by tiny bumps called papillae. Thousands of taste buds cover the papillae's surfaces. Taste buds are nerve-like cells that link to nerves that go into the brain. The tongue is held in place by webs of strong tissue and mucosa. The frenum is the thread that holds the front of the tongue. The tongue is attached to the hyoid bone in the rear of the mouth.

• The tongue is necessary for chewing and swallowing food, as well as speaking.
• Sweet, sour, bitter, and salty are the four most prevalent flavours.
• When there is glutamate intake, tongue get a fifth flavour called umami (present in MSG).
• The tongue has many nerves that aid in the detection and transmission of taste information to the brain.
• As a result, all regions of the tongue may perceive these four basic flavours.

Also Read Tongue Diagram

---

Anatomy of Tongue

[Click Here for Sample Questions]

The tongue is a pink, muscular organ that is normally found within the mouth cavity. The products of the main and minor salivary glands keep it wet, which benefits the organ by facilitating deglutition, speaking, and gustatory perception. While the length of the tongue varies greatly across individuals, the average size is around 10 cm long.

• The tongue is a mass of muscle that can be divided into different parts based on its regions.
• This differentiation is helpful to connect its structure to specific unique functions.
• The bumps on the tongue are called papillae.
• These vary in shape and location and are associated with taste buds.
• The muscles within and surrounding the tongue control its movement. 

Also Read:

---

Different parts of the tongue

[Click Here for Sample Questions]

When seen from the surface of the tongue, the tongue may be divided into several sections. This is significant because various regions of the tongue may be supplied by different nerves and blood arteries.

• The central or terminal sulcus, located about two-thirds of the way from the tongue's tip, is one of the most important tongue landmarks.
• The midline groove divides the tongue into right and left halves, and the fibrous lingual septum sits just beneath the groove's surface.
• The bottom of the tongue is covered by a thin, transparent mucous membrane.

The lingual frenulum is a wide midline fold of mucosa that runs from the tongue side of the gums (or gingiva) to the tongue's bottom surface. The frenulum links the tongue to the mouth's floor while enabling the tip to move freely. It is worth noting that the submandibular salivary gland has a duct that exits beneath the tongue. These are general descriptions of the tongue's gross parts:

• The root is commonly defined as the back third of the tongue.
• It is somewhat set in position and lies low in the mouth and towards the neck.
• It is connected to the hyoid bone and the mandible (lower jaw).
• It is close to two muscles: the geniohyoid and mylohyoid muscles.
• Body is the remainder of the tongue, particularly the two-thirds in front of the sulcus.
• It is very movable and serves a variety of purposes.
• Tip of the tongue is called apex.
• It is a pointy part at the front of the mouth. It is also quite mobile.
• Dorsum is the curled top surface towards the back.
• The terminal sulcus has a V-shaped groove on it.
• Inferior surface is located beneath the tongue.

---

Tongue Muscle Types

[Click Here for Sample Questions]

Most muscles function to connect one bone to another, generally via a tendon.  A boneless mass of tongue that may protrude, fold, invert, lay flat, or fill the mouth as desired. The muscles of the tongue have two types of actions: intrinsic muscles and extrinsic muscles:

i. Intrinsic Muscles

The superior longitudinal, inferior longitudinal, transverse, and vertical muscles of the tongue are the four paired intrinsic muscles. the regions of tongue are linked to the intrinsic muscles. These muscles influence the form and size of the tongue. The hypoglossal nerve provides motor innervation to the intrinsic muscles of the tongue. The role of the intrinsic muscles is explained further below:

• Superior longitudinal: Curls the tip and sides of the tongue upward and shortens the tongue.
• Inferior longitudinal: Curls the tip of the tongue downward and shortens the tongue.
• Transverse: Narrows and elongates the tongue, increasing its height and causing it to stick out (protrude).
• Vertical: Flattens and broadens the tongue within the mouth, causing it to protrude or push against the front teeth.

ii. Extrinsic Muscles

The extrinsic tongue muscles are a set of four tongue muscles. They all come from outside the mouth, as opposed to the intrinsic muscles of the tongue. They are fully contained within the tongue and have no exterior attachments. They change the location of the tongue, whereas the intrinsic tongue muscles change its form. The four muscles are as follows:

• The genioglossus is a big fan-shaped muscle that provides the majority of the tongue's mass.
• It lowers the tongue and may pull it forward, causing it to protrude or even wag back and forth.
• Hyoglossus is a slender, four-sided muscle that lowers and draws the tongue back into the mouth.
• Styloglossus is tiny, short muscle containing fibres that connect to the hyoglossus muscle.
• It can retract and pull up the tongue to form a trough for swallowing a bolus of food.
• Palatoglossus is a part of the soft palate rather than the tongue, it acts to raise the rear section of the tongue.

Read More: Prokaryotic and Eukaryotic Cells

---

Types Of Papillae

[Click Here for Sample Questions]

The front surface of the tongue is covered in papillae. These can come in a variety of forms, sizes, and functions. Many of these are connected with taste buds, while others may provide additional functions. Although there are no papillae on the back of the tongue, underlying lymphatic tissue may give it an uneven, cobblestone look. Consider the following general observations regarding papillae:

Vallate papillae:

These big, flat-topped bumps are found around two-thirds back on the tongue's surface, right in front of the terminal sulcus. They are encircled by deep pits into which ducts from fluid-producing glands open, and their walls are covered in taste buds.

Foliate papillae:

These tiny folds of the mucosa surface of the tongue are situated on the sides and are poorly developed in humans. Taste receptors are also found in taste buds.

Filiform papillae:

These elongated and numerous bumps are seen in V-shaped rows parallel to the terminal sulcus. They have nerve endings that are touch sensitive. They have a scaly, threadlike, pinkish-grey appearance and can make the tongues of some animals (such as cats) very harsh. These papillae are more crosswise at the tongue's tip (arranged transversely).

Nerves

The hypoglossal nerve (also known as cranial nerve XII) innervates all tongue muscles except the palatoglossus, which is innervated by a branch of the pharyngeal plexus. The lingual nerve provides sensation, including touch and temperature, to the anterior two-thirds of the tongue's surface (a branch from the trigeminal nerve). Taste is a unique sense that arises from the chorda tympani nerve, which branches from the face nerve. A branch of the glossopharyngeal nerve innervates the rear third of the tongue's general and particular sensations.

Blood Supply

Blood supply is achieved by artery and vein.

Artery:

The lingual artery, a branch of the external carotid artery, supplies the muscles of the tongue. It splits off from it in the neck at the larger horn of the hyoid bone. Then it travels upwards, loops down, and continues forward with the hyoglossus muscle through the oropharyngeal triangle. Following that, it moves forward between the genioglossus and hyoglossus muscles until it reaches the tip of the tongue.

• Along the way, the artery gives rise to the dorsal lingual arteries.
• It feed the root of the tongue, and the deep lingual arteries, which supply the tongue's body.
• The lingual artery serves the mucosa of the oral cavity floor, the sublingual gland, and the gingiva.

Veins:

The paired deep lingual veins and a single dorsal lingual vein provide for venous drainage of the tongue. The course of the dorsal lingual vein is similar to that of the dorsal lingual arteries. The deep lingual veins, on the other hand, begin at the tip of the tongue, travel posteriorly to the lingual frenulum with the deep lingual arteries, and then join the sublingual vein. The sublingual vein either drains straight into the internal jugular vein in the neck, or it merges with the lingual vein. It then feeds to the internal jugular vein at the start of the lingual artery.

Read More: Energy Currency of the Cell

---

Functions of Tongue

[Click Here for Sample Questions]

While the tongue has numerous functions, its primary function is to assist us in eating by allowing us to suck, convert food into a swallowable form, and initiate the swallowing process. It is necessary for sucking and nursing, chewing, grinding, salivating, tasting, touching, speaking, and protecting the body against pathogens, in addition to eating.

The tongue is a collection of muscles coated by a mucous membrane that is essential for taste sense. Aside from its apparent involvement in eating, it also plays an important role in speaking and may even impact breathing, notably in sleep. 

Eating and swallowing

Consider how the tongue assists a person in eating and swallowing food and liquids. After the teeth have taken a bite with the assistance of the powerful jaw muscles, the food must be broken down into smaller pieces before it can be safely ingested. The tongue aggressively transports food around in the mouth, preparing it for further deterioration by the teeth. The food is combined with saliva, eventually forming a manageable quantity known as a bolus that may be pushed into the pharynx before being swallowed and going into the stomach via the oesophagus. The tongue may also aid in oral cleaning by preventing food from coming into prolonged contact with the teeth.

Taste

Taste receptors in our taste buds are responsible for our capacity to taste food. According to several sources, taste buds renew every 8-12 days on average; however, some survive considerably longer. There are three types of taste buds as well:

• Fungiform taste buds papillae are of mushroom-shaped and situated in the tongue's core.
• Circumvallate taste buds papillae are in the rear of the tongue and have an inverted V shape.
• They're also far bigger and more complicated.
• Foliate taste buds papillae are located on the tongue's lateral sides.

The tongue aids in determining what could be appetising based on the perception of taste detected by the taste buds. The fundamental taste sensations are as follows: sweet, salty, sour, bitter, and savoury (umami). 

Speech:

The tongue has the ability to generate more than 90 words each minute utilising over 30 distinct movements. That's because it serves a purpose in assisting us in speaking. Speech is the result of air leaving the lungs through the mouth, and humans can only interpret noises from the throat when the tongue, lips, and teeth work together.

• Without appropriate tongue placement, it is impossible to create words and talk.
• This is due to the above-mentioned intrinsic and extrinsic muscles, which change the shape and location of the tongue.
• This aids in the proper articulation of sounds, and tongue dysfunction may result in a significant speech impairment.

​Mastication:

It simply refers to the process of mixing crushed up food particles with naturally existing saliva. Mastication occurs along with grinding, which occurs when teeth reduce big food particles to tiny ones. So, tongue chews the food between the teeth before combining it with saliva.

Breathing:

Breathing may be hampered if the tongue is positioned too far back in the throat. When mouth breathing is present, this is more likely to happen. The mouth is kept closed during normal nasal breathing, and the lower jaw is held forward when the teeth come together. This decreases the possibility of the tongue obstructing the airway. The movement of the tongue that occurs with mouth breathing during sleep can induce snoring and obstructive sleep apnea.

Other functions:

The tongue also serves numerous other functions. It may safeguard the body with a gag response, preventing the consumption of unpleasant and even dangerous substances. 

Furthermore, the tongue provides a route for medicines to be absorbed quickly. Nitroglycerin, in particular, is used to widen the blood arteries of the heart when significant chest discomfort occurs. When a tablet or spray is placed beneath the tongue, the medicine dissolves rapidly and reaches the veins in less than a minute.

Also Read: 

---

Things to Remember

• The tongue is a muscle organ that is located in the mouth. 
• The rough texture of the tongue is caused by tiny bumps called papillae.
• Thousands of taste buds cover the papillae's surfaces. 
• The tongue is necessary for chewing and swallowing food, as well as speaking.
• Sweet, sour, bitter, and salty are the four taste buds.
• The tongue has many nerves that aid in the detection and transmission of taste information to the brain. 
• The central or terminal sulcus is one of the most important part.
• The functions of the tongue are helping in speech, eating and swallowing, taste, mastication or chewing, helps in breathing etc.